1. Field of the Invention
The present invention is directed to a ventilator of the type having a tube adapted for communication with a patient""s airways for exchanging gas with the patient in an inspiration phase and an expiration phase of a breathing cycle.
2. Description of the Prior Art
In respiratory care, particularly when a tracheal tube is used for connecting a patient to the ventilator, the patient sometimes finds it hard to communicate with others. Even if the patient succeeds in speaking some words, the ventilator often interprets this as a difference between the volume of inspired and expired breathing gas. This triggers an alarm that effectively drowns out any words spoken by the patient.
Corresponding problems can arise with ventilators with limited adaptability or inappropriate settings for the respiratory treatment. If the patient attempts to communicate the discomfort of struggling against the ventilator, this might not be noticed by anyone. When a staff member finally arrives (e.g. because a volume alarm is sounded), the patient may not be able to reveal her/his discomfort. No alarm might be triggered if the influence of the volumes is less pronounced.
Another problem exists with regard to patients who are conscious but too weak (or paralyzed) to be able to use the alarm button to attract the staff""s attention. Therefore, these patients may experience pain or general discomfort without being able to summon help.
An object of the present invention is to provide a ventilator that solves the aforementioned problems, at least in part.
The above object is achieved in accordance with the principles of the present invention in a ventilator for respiratory care having a tube adapted for connection to a patient, and having a sound detector which detects and identifies sounds made by the patient, and a control unit operatively connected to the sound detector for influencing at least one function in the ventilator on the basis of sounds from the patient identified by the sound detector.
One or a number of new special functions can be added and performed by the ventilator with the use of a sound detector devised to detect sounds made by the patient, especially when the detected sounds can be interpreted as having been intentionally made by the patient.
Needless alarms (which would otherwise prevent the patient""s voice from being heard) in particular can be inhibited and necessary alarms generated (e.g. summoning staff with an optical signal or some form of remote signal). The latter is especially advantageous when the patient makes unintentional sounds caused by e.g. pain.
Inhibition of alarms can be limited to certain types of discrepancies, e.g. a difference between inspired and expired volumes, and even limited to a certain sound magnitude, e.g. with specific upper and lower limits.
Other functions in the ventilator that could be affected on the basis of sounds from the patient are the volume of gas delivered in inspiratory phases (increase/decrease), the duration of inspiratory and expiratory phases (shorter/longer), changes in the respiratory mode (from controlled respiration to assisted respiration, from assisted respiration to spontaneous respiration or between different kinds of controlled, supported and spontaneous respiration).